1. Cross-reference to Related Applications
The present application is related to the co-pending application of Robert M. Gibbon, entitled "METHOD OF MANUFACTURING ELASTOMERIC ENGINE COMPONENTS", filed Nov. 6, 1989, Ser. No. 07/432,081, and assigned to the assignee of the present invention.
2. Field of the Invention
The present invention relates to elastomeric engine components and, specifically, to a method for manufacturing an improved engine gasket having an oil impermeable surface to prevent thermocycling of engine oil through the gasket during use.
3. Description of the Prior Art
A variety of a elastomeric materials are used as components found in the engine compartment of a vehicle. These elastomeric materials include natural or organic and synthetic rubbers, for instance, EPDM, SBR, butyl, nitrile and neoprene, chlorosulfonated polyethylene, fluorocarbon containing compounds, urethanes and the like. Elastomeric engine components such as engine gaskets and spark plug boots can advantageously be formed of silicone rubber which provides enhanced stability at elevated temperatures and resistance to contamination by engine fumes, leakage and the like.
In spite of the many advantages offered by silicone rubber as a gasket material, in some specific applications the inner side of the gasket which is exposed to hot oil in the vehicle engine tends to absorb some of the oil and swells slightly. As the gasket and confronting metal surfaces of the engine cool, the absorbed oil is squeezed out of the gasket in both the inner and outer directions. This "thermocycling" which results from alternate engine heating and cooling causes the absorbed oil to be pumped slowly through the silicone rubber gasket until it permeates through the cross-sectional thickness of the gasket from the inner side to the outer side.
The present invention has as its object to provide an improved engine gasket with an oil impermeable inner surface which prevents thermocycling of absorbed oil and, hence, permeation of the gasket.
The invention has particular application to an engine gasket formed of silicone rubber and used as an engine component of a vehicle engine such as the engine of a passenger automobile.